From d445ea5fc449ac08bf663a7f66d414f66c985eef Mon Sep 17 00:00:00 2001
From: Matthias Diener <mdiener@illinois.edu>
Date: Thu, 15 Sep 2022 15:58:49 -0500
Subject: [PATCH 1/2] add --before feature

---
 install.sh | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/install.sh b/install.sh
index 1acc252..40939ac 100755
--- a/install.sh
+++ b/install.sh
@@ -15,6 +15,11 @@ if ! command -v mpicc &> /dev/null ;then
     exit 2
 fi
 
+function version
+{
+  echo "$@" | awk -F. '{ printf("%d%03d%03d%03d\n", $1,$2,$3,$4); }';
+}
+
 
 usage()
 {
@@ -32,6 +37,7 @@ usage()
   echo "  --git-ssh             Use SSH-based URL to clone mirgecom."
   echo "  --debug               Show debugging output of this script (set -x)."
   echo "  --skip-clone          Skip cloning mirgecom, assume it will be manually copied."
+  echo "  --before=DATE         Check out a specific version of the branch before DATE (in the form yyyy-mm-dd)."
   echo "  --help                Print this help text."
 }
 
@@ -59,6 +65,9 @@ opt_git_ssh=0
 # Skip cloning mirgecom
 opt_skip_clone=0
 
+# Check out version of the branch before a certain date
+opt_before_date=
+
 while [[ $# -gt 0 ]]; do
   arg=$1
   shift
@@ -110,6 +119,9 @@ while [[ $# -gt 0 ]]; do
     --skip-clone)
         opt_skip_clone=1
         ;;
+    --before=*)
+        opt_before_date=${arg#*=}
+        ;;
     --help)
         usage
         exit 0
@@ -155,6 +167,14 @@ if [[ $opt_skip_clone -eq 0 ]]; then
   fi
 fi
 
+if [[ -n $opt_before_date ]]; then
+  if [[ $(version "$(git --version | awk '{print $3}')") -ge $(version "2.23.0") ]]; then
+    echo "Your git version is too old for the --before option, please upgrade to 2.23 or newer."
+    exit 4
+  fi
+  git checkout "$(git rev-list -n1 --before=$opt_before_date $mcbranch)"
+fi
+
 echo "==== Create $env_name conda environment"
 
 [[ -z $conda_env_file ]] && conda_env_file="$mcsrc/conda-env.yml"

From 3290e02a61c5219bc9ccb762ca29920ea884f4ae Mon Sep 17 00:00:00 2001
From: Matthias Diener <mdiener@illinois.edu>
Date: Thu, 15 Sep 2022 16:15:49 -0500
Subject: [PATCH 2/2] add comment

---
 install.sh | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/install.sh b/install.sh
index 40939ac..e113a94 100755
--- a/install.sh
+++ b/install.sh
@@ -173,6 +173,8 @@ if [[ -n $opt_before_date ]]; then
     exit 4
   fi
   git checkout "$(git rev-list -n1 --before=$opt_before_date $mcbranch)"
+  # Maybe use https://github.com/astrofrog/pypi-timemachine for pip.
+  # What to do with conda?
 fi
 
 echo "==== Create $env_name conda environment"